Energy, Exergy,\nand Economic Analysis of a Low-Energy\nConsumption CO<sub>2</sub> Capture System with Ionic Liquid [DEME][TF<sub>2</sub>N]

This study aimed to reduce the energy\nconsumption of the CO<sub>2</sub> capture system by coupling the CO<sub>2</sub> capture process\nwith an energy recovery element and screening for a solvent with a\nbetter CO<sub>2</sub> capture performance. The high-pressure N<sub>2</sub> and O<sub>2</sub> mixture, which was not absorbed by the\nionic liquid during the absorption process, expanded in the turbine\nto output work in the energy recovery element. The heat-transfer fluid\nin the heat exchangers between the compressors and turbines transferred\ncompression heat from the flue gas to the N<sub>2</sub> and O<sub>2</sub> mixture to increase the amount of energy recovered. Subsequently,\nthe heat-transfer fluid flowed into the desorber to utilize the remaining\nheat to facilitate desorption. In addition, the COSMO-RS method was\nused to screen for the best CO<sub>2</sub> capture solvent, diethylmethyl(2-methoxyethyl)ammonium\nbis(trifluoromethylsulfonyl)imide ([DEME][TF<sub>2</sub>N]). We measured\nthe solubilities of N<sub>2</sub>, O<sub>2</sub>, and CO<sub>2</sub> in [DEME][TF<sub>2</sub>N] and the specific heat capacity of [DEME][TF<sub>2</sub>N] for system analysis. Energy, exergy, and economic analyses\nwere conducted to comprehensively evaluate the performance of the\nproposed system. The analysis results indicated that the total energy\nconsumption was 0.703 GJ/tCO<sub>2</sub> at an absorption pressure\nof 1000 kPa and a heat-transfer fluid rate of 1800 kg/h.